\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}
\fancyhead[LE,RO]{\thepage}
\fancyhead[RE]{\leftmark}
\fancyhead[LO]{\rightmark}
\fancypagestyle{plain}{
  \fancyhf{}
  \renewcommand{\headrulewidth}{0pt}
}
\renewcommand\chaptermark[1]{\markboth{\chaptername\ \thechapter: #1}{}}
\renewcommand\sectionmark[1]{\markright{\thesection: #1}}
